Control valve with annular poppet check valve

ABSTRACT

Embodiments of the invention provide a control valve including a control valve body having an inlet passage, an outlet passage, a workport, and a chamber arranged in a fluid path between the workport and the outlet passage. The control valve further includes an annular poppet slidably received within the chamber and to selectively engage a poppet seat to inhibit fluid flow through the fluid path when a pressure in the fluid path is less than a predefined pressure level, and a valve element slidably received within the control valve body to selectively provide fluid communication between the inlet passage and the workport and selectively provide fluid communication between the workport and the outlet passage along the fluid path. The poppet is biased towards the poppet seat by an elastic element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is based on, claims priority to, andincorporates herein by reference in its entirety, U.S. ProvisionalPatent Application No. 62/114,842, filed Feb. 11, 2015, and entitled“Control Valve with Annular Poppet Check Valve.”

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE DISCLOSURE

The present invention relates generally to control valves and, morespecifically, to a control valve that includes an annular poppet checkvalve.

In automotive engines, an increasing number of control functions arebeing actuated using engine oil pump pressure. For cylinder deactivationsystems, it is necessary to ensure that moving components, such ascylinder valve lifters, are exposed to positive oil pressure forlubrication. Pressure between the cylinder valve lifters and the oilcontrol valve used to deactivate the lifters also helps to reducehydraulic compliance that could limit the pressure response of theengine cylinder deactivation system.

Referring now to FIG. 1, in some control valves used in engine cylinderdeactivation systems, such as cylinder deactivation system 100, an oilpump 103 can supply pressurized fluid to a control valve 102 that can beconnected to a cylinder valve lifter 101. The oil pressure between thecylinder valve lifter 101 and the oil control valve 102 can bemaintained by using low pressure check valves 104 built into the oilcontrol valve 102. These low pressure check valves 104 can include balls106 held against ball seats 112 by springs 108. The balls 106 can blockthe flow of the oil from the lifter passages 110 to an oil tank 111until the oil pressure in the lifter passages 110 creates a force on theball seats 112 greater than or equal to the force of the spring load.Once the oil pressure in the lifter passage 110 creates enough force,the check valve ball 106 can lift off of the ball seat 112, and the oilcan flow past the balls 106 as long as the pressure force exceeds thespring force. The oil flow into the lifter passage 110 can either besupplied by orifice 114 in the oil control valve 102 or an orifice 116positioned remotely from the control valve 102 between the cylindervalve lifter 101 and the pump 103.

There are some disadvantages to the ball style pressure check valves forapplication in an engine. In this typical arrangement, the passages,including the check valve seat area, are oriented radially outward fromthe valve bore 105. Sufficient space for the flow passage, seat area,ball, and spring is required. Having this space requirement means thatthe diameter of the valve body, and thus the cavity in the engine, haveto be large enough to accommodate these parts. Also, the flow passageinto the check valve and the ball seat area are necessarily the samesize, so the only way to increase the flow area in this design is toalso increase the ball size or use multiple check valves in parallel.Bigger balls and multiple check valves increase the size of the overallvalve package and the number of components. Further, the check valvesprings often are difficult to produce and assemble due to the low forceand spring rate design criteria required to maintain the typical lowhydraulic pressure.

Thus, it would be advantageous to have a control valve including a checkvalve that allows for more control over the flow rate of a fluid withouthaving to adjust the size of the check valve.

BRIEF SUMMARY OF THE DISCLOSURE

The aforementioned shortcomings can be overcome by providing a controlvalve that includes a check valve having an annular poppet that providesa large flow area and thereby reduces a pressure drop through the checkvalve.

In one aspect, the present invention provides a control valve includinga control valve body having an inlet passage, an outlet passage, aworkport, and a chamber arranged in a fluid path between the workportand the outlet passage. The control valve further includes an annularpoppet slidably received within the chamber and to selectively engage apoppet seat to inhibit fluid flow through the fluid path when a pressurein the fluid path is less than a predefined pressure level, and a valveelement slidably received within the control valve body to selectivelyprovide fluid communication between the inlet passage and the workportand selectively provide fluid communication between the workport and theoutlet passage along the fluid path. The control valve further includeselastic element to bias the annular poppet towards the poppet seat.

In some embodiments, the control valve body includes an outer bodyextending around an inner body with the chamber formed therebetween.

In some embodiments, the annular poppet extends around the inner body.

In some embodiments, the annular poppet defines a poppet approach areaon which the pressure in the fluid path acts upon, and the outer bodydefines an outer body diameter.

In some embodiments, a force provided by the elastic element on theannular poppet and the approach area determine the predefined pressurelevel.

In some embodiments, the outer body defines an outer body diameter and aratio of the approach area to the outer body diameter is between about1.5 and 3.5.

In some embodiments, the outer body defines an outer body diameter and aratio of the approach area to the outer body diameter is between about 2and 3.

In some embodiments, the control valve body includes a first valve seatbetween the inlet passage and the workport and a second valve seatbetween the workport and the outlet passage, and the valve element ismoveable between a first element position where the valve elementengages the first valve seat and a second element position where thevalve element engages the second valve seat.

In some embodiments, the control valve further includes at least onespring to bias the valve element toward one of the first elementposition and the second element position.

In some embodiments, the control valve further includes an actuator toactuate the valve element between the first element position and thesecond element position.

In some embodiments, the elastic element is a coil spring.

In some embodiments, the control valve is installed on an engine tooperate a cylinder valve lifter assembly.

In some embodiments, the inlet passage is connected to receive fluidfrom an oil pump on the engine and the outlet passage is connected to anoil reservoir on the engine.

In some embodiments, the workport is connected to an engine cylinderlifter assembly.

In another aspect, the present invention provides a control valveincluding a control valve body having an inlet passage, an outletpassage, a workport, a first valve seat between the inlet passage andthe workport, and a second valve seat in a fluid path between theworkport and the outlet passage. The control valve further includes avalve element moveable between a first element position where the valveelement engages the first valve seat and disengages the second valveseat, and a second element position where the valve element disengagesthe first valve seat and engages the second valve seat. The controlvalve further includes an annular poppet moveable between a firstposition where the annular poppet engages an annular poppet seat toinhibit fluid flow through the fluid path and a second poppet positionwhere the annular poppet disengages the annular poppet seat and fluidflow is provided through the fluid path. The annular poppet is moveablefrom the first poppet position towards the second poppet position whenpressure in the fluid path is greater than a predefined pressure level.The control valve further includes a spring to bias the annular poppettoward the first poppet position.

In some embodiments, the control valve body includes an annular chamberin the fluid path between the second valve seat and the outlet passageand the annular poppet is slidably received within the annular chamber.

In some embodiments, the control valve body includes an outer body intowhich an inner body is received, and the annular chamber and the annularpoppet each extend around the inner body.

In some embodiments, the inner body defines a bore in which the valveelement is slidably received.

In some embodiments, the annular poppet defines a poppet approach areaon which the pressure in the fluid path acts upon.

In some embodiments, a force provided by the elastic element on theannular poppet and the approach area determine the predefined pressurelevel.

In some embodiments, the outer body defines an outer body diameter and aratio of the approach area to the outer body diameter is between about1.5 and 3.5.

In some embodiments, the outer body defines an outer body diameter and aratio of the approach area to the outer body diameter is between about 2and 3.

In some embodiments, the control valve further includes a valve springto bias the valve element towards one of the first element position andthe second element position.

In some embodiments, the control valve further includes an actuator tomove the valve element between the first element position and the secondelement position.

These and other objects, advantages, and aspects of the inventions willbecome apparent from the following description. In the description,reference is made to the accompanying drawings which form a part hereofand in which there is shown a preferred embodiment of the invention.Such embodiment does not necessarily represent the full scope of theinvention and reference is made, therefore, to the claims herein forinterpreting the scope of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a prior control valve system including ball type checkvalves;

FIG. 2 shows a perspective view of a control valve including an annularpoppet check valve according to one embodiment of the invention;

FIG. 3 shows a partial cross-sectional view of the control valve of FIG.2 taken along line 3-3;

FIG. 4 shows a cross-sectional view of the control valve of FIG. 2 takenalong line 4-4 with an outlet fluid path closed; and

FIG. 5 shows the cross-section view of FIG. 4 with an outlet fluid pathopen.

DETAILED DESCRIPTION OF THE DISCLOSURE

One or more specific embodiments of the present invention will bedescribed below. It should be appreciated that in the development of anysuch actual implementation, as in any engineering or design project,numerous implementation specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The various aspects of the subject disclosure are now described withreference the drawings, wherein like reference numerals correspond tosimilar elements throughout the several views. It should be understood,however, that the drawings and detailed description hereafter relatingthereto are not intended to limit the claimed subject matter to theparticular form disclosed. Rather, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the claimed subject matter.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

In addition, references herein to directional relationships and movementsuch as up and down or inner and outer, refer to the relationship andmovement of the components in the orientation illustrated in thedrawings, which may not be the orientation of the components inpractice.

Referring now to the drawings and more specifically, referring to FIG.2, the present disclosure will be described in the context of anexemplary control valve 200 for deactivating an engine cylinder. It isto be appreciated that the control valve 200 can be used in otherapplications where fluid control is required, as would be understood byone of skill in the art. The reference to cylinder deactivation is notto be considered limiting in any way. As shown in FIG. 2, the controlvalve 200 can include a control valve body 202 coupled to an actuator204. A mounting flange 206 can be arranged between the control valvebody 202 and the actuator 204. The mounting flange 206 can enable thecontrol valve 200 to be coupled to, for example, an engine. The controlvalve body 202 can include an outer body 208 having a outlet passage 210and a workport 212 spaced longitudinally from the outlet passage 210.The outlet passage 210 can be formed by a plurality of outlet cutouts214 arranged circumferentially around a periphery of the outer body 208.The workport 212 can be formed by a plurality of workport cutouts 216arranged circumferentially around a periphery of the outer body 208.

Turning to FIG. 3, the outer body 208 can define a outer body diameterD_(o) that defines a size of a cavity in which the control valve body202 can be mounted. The control valve body 202 can include an inner body218 arranged within the outer body 208 and can define a bore 220 withinwhich a valve element 222 is slidably received. The actuator 204, whichmay be in the form of a solenoid, can operate on an end 224 of the valveelement 222 causing the valve element 222 to move with respect to theinner body 218 to engage and disengage a first valve seat 224 and asecond valve seat 226. That is, the valve element 222 is moveablebetween a first element position (FIG. 3) where the valve element 222engages the first valve seat 224 and disengages the second valve seat226, and a second element position where the valve element 222 engages asecond valve seat 226 and disengages the first valve seat 224. When thevalve element 222 is in the first element position, as shown in FIG. 3,fluid communication can be inhibited between an inlet passage 228 of thecontrol valve 200 and the workport 212 and fluid communication can beprovided along a fluid path 232 between the workport 212 and a checkvalve 234. When the valve element 222 is in the second element position,fluid communication can be provided between the inlet passage 228 andthe workport 212, and fluid communication can be inhibited along thefluid path 232 between the workport 212 and the check valve 234. Theillustrated valve element 222 can be a poppet, however, in otherembodiments, the valve element 222 may be a spool.

A mesh filter 236 can be coupled to the outer body 208 adjacent to theinlet passage 228 and can be arranged upstream of the inlet passage 228.In some installations, the control valve 200 can be implemented in acylinder deactivation system where the inlet passage 228 receivespressurized fluid from an engine oil pump 238, and the workport 212 iscoupled to an engine cylinder valve lifter assembly 240.

The check valve 234 can inhibit fluid to flow from the outlet passage210 to the workport 212 and can comprise an annular poppet 242 arrangedwithin a check valve chamber 244 between the inner body 218 and theouter body 208. In some embodiments, the annular poppet 242, the innerbody 218, and the outer body 208 can be fabricated from plastic. Inthese embodiments, the annular poppet 242, the inner body 218, and theouter body 208 can be manufactured using a molding process. The annularpoppet 242 can extend around the inner body 218 and may slide up anddown with respect to the inner body 218. An elastic element 246 can beused to bias the annular poppet 242 toward an annular poppet seat 248formed on the outer body 208. In some embodiments, the elastic element246 is a coil spring. The annular poppet 242 can be moveable between afirst poppet position (FIG. 3) where the annular poppet 242 can beforced against the annular poppet seat 248 by the elastic element 246,and a second poppet position where the annular poppet 242 is forced awayfrom the annular poppet seat 248 by fluid pressure in the fluid path232. In the first poppet position, the annular poppet 242 seals againstthe annular poppet seat 248 thereby inhibiting fluid flow along thefluid path 232 and into the check valve chamber 244 which leads into theoutlet passage 210. The annular poppet 242 can define a poppet approacharea A_(p) on which pressure in the fluid path 232 can act on to biasthe annular poppet 242 towards the second poppet position. The poppetapproach area A_(p) can be defined, in part, by an annular poppetsurface 250 of the annular poppet 242.

When the pressure in the fluid path 232 acting on the poppet approacharea A_(p) exceeds a predefined level, defined by the elastic element246 and the pressurized area of the annular poppet 242, the annularpoppet 242 can move towards the second poppet position where itdisengages from the annular poppet seat 248 thereby enabling fluid flowthrough the fluid path 232 and past the check valve 234 to the outletpassage 210. At that time, engine oil may flow from the workport 212through the fluid path 232 into the check valve chamber 244 and onwardinto the outlet passage 210. In some installations, the outlet passage210 is coupled to a fluid tank 252, such as the engine oil pan.

For pressure in the fluid path 232 to be great enough to overcome theforce exerted by the elastic element 246 and the pressurized area of theannular poppet 242 and open the check valve 234, the valve element 222can be in the first element position where the fluid path 232 can beopen to allow fluid to enter from the workport 212 and act on theapproach area A_(p). In the illustrated embodiment, the lifter pressurefrom the engine cylinder valve lifter assembly 240 can be communicatedthrough the workport 212 and the fluid path 232 to apply a hydraulicforce on the approach area A_(p) of the annular poppet 242, tending tolift the annular poppet 242 away from the poppet seat 248, and open thecheck valve 234 and provide a fluid path to the outlet passage 210. Inthis way, the check valve 234 can limit the pressure in the fluid path232 (i.e., the lifter pressure exposed to the engine cylinder valvelifter assembly 240) to the pressure set by the elastic element 246 andthe pressurized area of the annular poppet 242.

Referring now to FIGS. 4 and 5, the actuator 204 of the control valve200 can include a housing 254 coupled to the mounting flange 206. Theactuator 204 can also include a solenoid 256 arranged within the housing254 and an armature 258 arranged within the solenoid 256. A solenoidspring 260 can bias the armature 258 into engagement with the valveelement 222. The force provided by the solenoid spring 260 that can biasthe valve element 222 towards the first element position can be greaterthan a force provided by a valve element spring 261 that can bias thevalve element 222 towards the second element position. Thus, when thesolenoid 256 is deactivated, the valve element 222 can be biased intothe first element position by the solenoid spring 260.

The actuator 204 can control the movement of the valve element 222between the first element position and the second element positionwithin the bore 220 of the inner body 218. As described above, when acontrol current is not applied to the solenoid 256 (i.e., the solenoid256 is deactivated), the fluid path 232 can open to workport 212 (i.e.,the valve element 222 can be in the first element position) allowing thefluid to flow from the cylinder valve lifter assembly 240 via theworkport 212 to the annular poppet 242 of the check valve 234. When acontrol current is applied to the solenoid 256, the armature 258 canmove “up” against the solenoid spring 260 to allow the valve element 222to move to the second element position where fluid communication betweeninlet passage 228 and workport 212 can be provided and fluidcommunication can be inhibited along the fluid path 232 between workport212 and the check valve 234.

In operation, the control valve 200 can be mounted within an enginecavity 262 of, for example, an engine, and the actuator 204 of thecontrol valve 200 can be in communication with, for example, an enginecontrol unit (ECU). The ECU can be configured to selectively activateand deactivate (i.e., selectively apply a control current) to thesolenoid 256 to move the valve element 222 between the first elementposition and the second element position. When the solenoid 256 isactivated, the valve element 222 can be moved into the second elementposition where the engine oil pump 238 can supply fluid to the inletpassage 228 and thereby to the engine cylinder valve lifter assembly 240via the workport 212. When the solenoid 256 is deactivated, the valveelement 222 can be biased into the first element position by thesolenoid spring 260 where fluid communication can be inhibited betweenthe inlet passage 228 and the workport 212. The engine oil pump 238 canstill provid fluid to the engine cylinder valve lifter assembly 240 viaan orifice 264 positioned remotely from the control valve 200 andarranged between the engine cylinder valve lifter assembly 240 and theengine oil pump 238. In other embodiments, the control valve 200 mayincluding an orifice arranged within the control valve body 202 toprovide fluid to the engine cylinder valve lifter assembly 240.

While the valve element 222 is in the second element position, fluid canflow from the engine cylinder valve lifter assembly 240 along the fluidpath 232 to the approach area A_(p) of the check valve 234. As describedabove, when the pressure in the fluid path 232 exceeds the force exertedby the elastic element 246 and the pressurized area of the annularpoppet 242, the annular poppet 242 can be moved from the first poppetposition (FIG. 4) towards the second poppet position (FIG. 5) therebyopening the check valve 234. In this way, the check valve 234 acts toregulate the pressure in the fluid path 232 to at least a pressuredefined by the force of the elastic element 246 and the pressurized areaof the annular poppet 242. Thus, during operation, the control valve 200can ensure that the engine cylinder valve lifter assembly 240 alwaysreceives positive fluid pressure either from the engine oil pump 238 orthe regulation provided by the check valve 234.

Exemplary advantages of the above-described control valve 200 or othercontrol valves designed or created using the above-described techniquesor properties, will be discussed below with reference to FIGS. 3-5. Byno means is the following an exhaustive list of the numerous advantagesprovided by the invention, as will be understood by one of skill in theart.

The annular shape defined by the annular poppet 242 of the check valve234 can provide a larger diameter, for example when compared to the ballseats 112 of the prior art control valve 102 of FIG. 1 and, thus, thecheck valve 234 can open a much larger flow area (when the annularpoppet 242 moves towards the second poppet position) between theworkport 212 and the outlet passage 210. This larger flow area canprovide a reduced pressure drop through the check valve 234 allowingmore flow through the check valve 234 and, in the application ofcylinder valve deactivation, faster lifter pin movement (i.e., fluid canmore efficiently flow from the engine cylinder valve lifter assembly 240to the fluid tank 252 with a reduced pressure drop through the checkvalve 234). Additionally, the reduced pressure drop provided by thelarger flow area of the annular poppet 242 can enable the check valve234 to more consistently regulate the pressure in the fluid path 232(when the valve element 222 is in the first element position) over alarge range of fluid flowrates which can occur with changes in oilpressure and temperature. Further, the larger diameter provided by theannular poppet 242 can simplify the manufacture of the elastic element246 because of the higher forces, for example when compared with thecheck valve springs 108 of the prior art control valve 102 of FIG. 1,needed to counter the larger poppet area.

The annular poppet 242 of the check valve 234 can also reduce packagingsize of the control valve 200, when compared to the control valve 102.That is, the annular poppet design implemented in the control valve 200can reduce a diameter of the cavity 262 in which the control valve 200can be mounted. Further, in comparison to the prior control valve 102with the balls 106, the assembly of the control valve 200 may besimplified with the elastic element 246 and the annular poppet 242 beingplaced over the inner body 218 and captured by the outer body 208.

The larger flow area and reduced packaging size provided by the controlvalve 200 can be achieved by proper geometric design (i.e., the use ofthe annular poppet 242). These advantages can be governed by a geometricrelationship between the poppet approach area A_(p) and the outer bodydiameter D_(o). In one embodiment, the control valve 200 can define aratio of the approach area A_(p) to the outer body diameter D_(o) thatis between about 1.5 and about 3.5. In another embodiment, the controlvalve 200 can define a ratio of the approach area A_(p) to the outerbody diameter D_(o) that is between about 2 and about 3.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. For example, the controlvalve body 202 may include more passages and/or fluid paths than thepassages and fluid paths 210, 212, 228, and 232. Also, the control valve200 may be used in any applicable circumstance for obtaining the desiredresult of allowing or inhibiting fluid flow from one device to another.

Whilst the invention has been described above, it extends to anyinventive combination of features set out above or in the followingdescription. Although illustrative embodiments of the invention aredescribed in detail herein with reference to the accompanying drawings,it is to be understood that the invention is not limited to theseprecise embodiments. Furthermore, it is contemplated that a particularfeature described either individually or as part of an embodiment can becombined with other individually described features, or parts of otherembodiments, even if the other features and embodiments make no mentionof the particular feature. Thus, the invention extends to such specificcombinations not already described.

Thus, while the invention has been described in connection withparticular embodiments and examples, the invention is not necessarily solimited, and that numerous other embodiments, examples, uses,modifications and departures from the embodiments, examples and uses areintended to be encompassed by the claims attached hereto. The entiredisclosure of each patent and publication cited herein.

What is claimed is:
 1. A control valve comprising: a control valve bodyhaving an inlet passage, an outlet passage, a workport, and a chamberarranged in a fluid path between the workport and the outlet passage; anannular poppet slidably received within the chamber and to selectivelyengage a poppet seat to inhibit fluid flow through the fluid path when apressure in the fluid path is less than a predefined pressure level; avalve element slidably received within the control valve body toselectively provide fluid communication between the inlet passage andthe workport and selectively provide fluid communication between theworkport and the outlet passage along the fluid path; and an elasticelement biasing the annular poppet toward the poppet seat.
 2. Thecontrol valve of claim 1, wherein the control valve body comprises anouter body extending around an inner body with the chamber formed therebetween.
 3. The control valve of claim 2, wherein the annular poppetextends around the inner body.
 4. The control valve of claim 2, whereinthe annular poppet defines a poppet approach area on which the pressurein the fluid path acts upon.
 5. The control valve of claim 4, wherein aforce provided by the elastic element on the annular poppet and theapproach area determine the predefined pressure level.
 6. The controlvalve of claim 4, wherein the outer body defines an outer body diameterand a ratio of the approach area to the outer body diameter is betweenabout 1.5 and about 3.5.
 7. The control valve of claim 4, wherein theouter body defines an outer body diameter and a ratio of the approacharea to the outer body diameter is between about 2 and about
 3. 8. Thecontrol valve of claim 1, wherein the control valve body comprises afirst valve seat between the inlet passage and the workport and a secondvalve seat between the workport and the outlet passage; and the valveelement is moveable between a first element position where the valveelement engages the first valve seat and a second element position wherethe valve element engages the second valve seat.
 9. The control valve ofclaim 8, further comprising at least one spring to bias the valveelement toward one of the first element position and the second elementposition.
 10. The control valve of claim 8, further comprising anactuator to actuate the valve element between the first element positionand the second element position.
 11. The control valve of claim 1,further comprising an actuator to move the valve element between a firstelement position and a second element position.
 12. The control valve ofclaim 1, wherein the elastic element is a coil spring.
 13. The controlvalve of claim 1, wherein the control valve is installed on an engine tooperate a cylinder valve lifter assembly.
 14. The control valve of claim13, wherein the inlet passage is connected to receive fluid from an oilpump on the engine and the outlet passage is connected to an oilreservoir on the engine.
 15. The control valve of claim 13, wherein theworkport is connected to an engine cylinder valve lifter assembly.
 16. Acontrol valve comprising: a control valve body having an inlet passage,an outlet passage, a workport, a first valve seat between the inletpassage and the workport, and a second valve seat in a fluid pathbetween the workport and the outlet passage; a valve element moveablebetween a first element position where the valve element engages thefirst valve seat and disengages the second valve seat, and a secondelement position where the valve element disengages the first valve seatand engages the second valve seat; an annular poppet moveable between afirst position where the annular poppet engages an annular poppet seatto inhibit fluid flow through the fluid path and a second poppetposition where the annular poppet disengages the annular poppet seat andfluid flow is provided through the fluid path, wherein the annularpoppet is moveable from the first poppet position towards the secondpoppet position when pressure in the fluid path is greater than apredefined pressure level; and a spring to bias the annular poppettoward the first poppet position.
 17. The control valve of claim 16,wherein the control valve body comprises an annular chamber in the fluidpath between the second valve seat and the outlet passage, wherein theannular poppet is slidably received within the annular chamber.
 18. Thecontrol valve of claim 17, wherein the control valve body comprises anouter body into which an inner body is received, the annular chamber andthe annular poppet each extend around the inner body.
 19. The controlvalve of claim 18, wherein the inner body defines a bore in which thevalve element is slidably received.
 20. The control valve of claim 18,wherein the annular poppet defines a poppet approach area on which thepressure in the fluid path acts upon.
 21. The control valve of claim 20,wherein a force provided by the elastic element on the annular puppetand the approach area determine the predefined pressure level.
 22. Thecontrol valve of claim 20, wherein the outer body defines an outer bodydiameter and a ratio of the approach area to the outer body diameter isbetween about 1.5 and about 3.5.
 23. The control valve of claim 20,wherein the outer body defines an outer body diameter and a ratio of theapproach area to the outer body diameter is between about 2 and about 3.24. The control valve of claim 16, further comprising a valve spring tobias the valve element toward one of the first element position and thesecond element position.
 25. The control valve of claim 16, furthercomprising a actuator to move the valve element between the firstelement position and the second element position.